The present invention concerns a carpet-integrated foot cushion serving as a passive restraint component in a vehicle and as a device for reducing the danger of injury in the foot and leg areas of a person sitting on a seat positioned in the interior of a vehicle in case of accident-related deformation of the footwell according to German patent 196 39 467.
According to this patent, the footwell is provided in two embodiments with a gas bag of an associated air-bag module into which gas from a gas generator is introduced in a sudden burst as a result of a trigger signal, whereupon the gas bag quickly fills up the footwell in question to the specified degree in order to form a dampening cushion for the foot area before the dashboard intrudes into the interior of the vehicle.
It is proposed according to the principal patent, that it is necessary to position and suitably secure a discrete gas bag in the footwell in question. This involves increased effort and higher costs.
On the other hand, vehicles of newer design possess in the footwell a floor covering which, compared to previous floor coverings, is enhanced at least to include sound-absorbing features. In particular, modern floor coverings exhibit a sound-absorbing layer which is covered by the actual carpet layer.
From this background, it is the object of the present invention to further develop the device of the above-mentioned type in order to be able to realize the arrangement of a dampening foot cushion as economically as possible.
This problem is solved through the device described in the first claim. Additional advantageous embodiments result from the subclaims.
As already mentioned, an assumption for the inventive further development of the device of the above-mentioned type is that the footwell be lined with a floor covering consisting of a sound-absorbing layer and a superimposed carpet.
According to the present invention, the foot cushion in the footwell is formned between the sound-absorbing, layer and the carpet of the floor covering, the gas from the gas generator being directed into the space between the sound-absorbing layer and the carpet and the carpet being secured only at certain points to the sound-absorbing layer in the area of the developing foot cushion.
Thus, in the present case, a discrete gas bag is no longer used; rather, the multilayered nature of modern floor coverings is utilized in rapidly forming a foot cushion between the floor-covering layers. The multilayered nature of modern floor coverings therefore permits forgoing integration of a conventional gas bag. Assuming modification of the production process, the solution according to the present invention even makes it possible to integrate the inflatable foot cushion into the production process from the very beginning. Thus, the cost of the foot cushion can be held extremely low, which can lead to broad acceptance on the market.
The permeability of the foot cushion makes possible a so-called venting, which permits the escape of the gas from the foot cushion following inflation. This results from the gas permeability of the sound-absorbing layer and the carpet, i.e., of the entire floor covering.
According to an advantageous further development, in the area of the foot cushion forming in case of an accident, the carpet is secured to the sound-absorbing layer only at predetermined tear or break points. With a nonactivated gas generator, the securing of the carpet at the said tear or break points avoids the formation of folds in the carpet. On the other hand, these tear or break points permit sudden inflation of the foot cushion to full size within a few milliseconds following activation of the gas generator. The securing of the carpet to the sound-absorbing layer is eliminated as a result of the fact that the underside of the carpet tears away from the points of attachment. A predictable formation of the foot cushion is thus guaranteed.
According to an advantageous embodiment, the gas generator directing the gas into the foot cushion is a two-stage gas generator. To this generator can be attached, for example, two separate pressure lines, one of which directs gas into the foot cushion of the present invention. The other pressure line could advantageously be connected, for example, with a frontal air bag. Upon triggering of the two-stage gas generator, both the foot cushion as well as the frontal air bag would thus be inflated. As a result, equipment needs (such as, e.g., several generators) are reduced to a minimum. The chronological sequence (e.g., how many milliseconds the foot cushion is to be inflated before the frontal air bag) can also be controlled in such a system.
Alternatively, it can be provided that the gas generator is a single-stage gas generator to which, however, several pressure lines are attached, the ratio of their flow diameters decisively influencing the chronological inflation behavior of the attached gas bag and foot cushion.
Naturally, it is also possible to provide a separate gas generator for the foot cushion, which can be activated separately from, for example, the frontal air bag.